Heating apparatus



Bea-31, 194-0. 4 w. M. HEPBURN 2,226,816

' HEATING APPARATUS Filed Nov. 11, 1957 2 Sheets-Sheet ,2

3m entor attorney 4 Patented Dec. 31 1940 HEATDJG APPARATUS William M. Hepburn, Ottawa Hills, Ohio, assignmto Surface Combustion Corporation, Toledo, Ohio, a corporation of New York Application November 11, 1937, Serial No. 174,086

.(Qli. 126-91) 1 Claim.

This invention relates to heating apparatus comprising a fuel-fired radiator tube for produc ing radiant heat in a furnace chamber; and the object of the invention is to increase the utility of such heating apparatus by the improvements hereinafter described.

In the accompanying drawings wherein .the preferred form of the invention is shown,

Fig. 1 is a side elevation, with parts in section, of the improved heating apparatus;

Fig. 2 is a fragmentary sectional view taken on line 2--2 of Fig. 1;

Fig. 3 is a sectional view of a burner associated with the intake end of the radiator tube;

- Fig. 4 is a fragmentary sectional view of parts shown in Fig. 1, and

Fig. 5 is-a cross-sectional View on line 5-5 of Fig. 4. 1

In the drawings, I6 indicates a portion of a wall of a furnace chamber. wherein is positioned a fuel-fired radiator tube H for producing radiant heat in the chamber. For convenience of illustration, the radiator tube is shown as of the hairpin type with its free ends extending out of the chamber through said wall. The tube is fired by a burner generally indicated at A. Coupled to the exhaust end of the radiator tube is an exhaust conduit comprising an elbow ii, a pipe [3, and

an exhaust fan it.

The exhaust pipe i3 is internally and externally provided with heat conducting fins i5 and 55' re 'spectively. Extending around the exhaust pipe is a casing 86 which at its upper end is open to the atmosphere and which at its lower end is in open communication, by way of a duct ill, with the burner A.

For illustrative purposes the burner A has been shown as comprising a plurality of gas discharge tubes it which project into the mouth ll of the radiator tube from an annular gas chamber [9 to which fuel gas is supplied by a supply pipe .20. Air for supporting combustion of the fuel dis charged in the tubes 18 is delivered. to the radifect of pulling in the radiator tube l i on the premix burner 26, the chamber 25 is provided with a relatively restricted passage 21 which is open to the atmosphere. Since the air and fuel gas which enter the mouth of the radiator tube are 5 not premixed, the flame of combustion will, therefore, be relatively long. The burner thus briefly described forms, per se, no part of the present invention.

Referring now more particularly to Fig. t, id indicates an open ended pipe which projects into the return leg of the radiator tube from the ex haust end thereof, the pipe passing through a wall of the elbow i2 as indicated airbl. Coupled to the outer end of the pipe is a tubular extension 32 which extends out of the casing It through a radiator tube H from the burner end thereof in order not only to withdraw gases of combustion vator mouth by means including the afo'remenfrom the radiator tube but also to induce a how I of combustion supporting air to the burner A. Since the inner end of the pipe 3i! which extends into the return leg of the radiator tube is open communication with the interior of said tube, it follows that suction which is effective in the re turn leg is also effective in the pipe 3t and consequently that air will flow into the outer end of the pipe 30 either by Way of the ports $35 or the ports 34, depending on the position of the adjusting sleeve 35. As shown in Fig.1, the pipe 3b extendsa substantial distance into the return leg of the radiator tube from the inside face of the fur nace wall Id. The air which enters the radiator tube from the discharge end of the pipe 30 will support combustion of the residual fuel in' the gases coming from the intake leg of the radiator tube.

Surrounding the pipe 30 from its discharge end to a point adjacent the furnace wall i 0 is a spiral web 35 for defining a spiral flow passage for the gases of combustion flowing out-of the return leg of the radiator tube. By causing the gases to flow in a spiral path they will be thoroughly stirred up and thus more effectively insure both combustion of the residual fuel and transfer of charge from the inner of the pipe 30, some of the air may be introduced intermediate the ends of the spiral web from a series of holes 31 in the pipe. It is desirable to cool the gases of combustion after they leave the radiator tube in the furnace and to this end the pipe is provided with openings shown as slot type holes 38 at a point relativ'ely close to the inside face of the furnace wall It. Since the air which flows through the casing I6 is preheated by indirect heat exchange with the waste gases of combustion, it will be readily appreciated that by proper adjustment of the sleeve the air which flows into the tube 30 may be either all preheated air or partially preheated air or all air at atmospheric temperature, depending on the adjustment of the sleeve 35. The heating effect of the residual fuel in the gases in the return leg of the radiatortube may, therefore, be controlled to a nicety.

The advantages of supplying preheated air to the fuel flowing into the intake end of .the radiator tube will be readily apparent without explanation. However, it is believed tobe novel to preheat the air by a heat exchanger around the exhaust conduit at apoint between the exhaust.

fan and the point of emergence of the radiator tube from the furnace chamber. An important result obtained by this arrangement is that the temperature of the exhaust gases is materially reduced before reaching the exhaust fan, thereby not only prolonging the life of the fan but also increasing its emcien'cy.

What I claim is:

In apparatus of the class described, the combination of a tube type radiator, a burner flring into one end of the radiator, an exhaust pipe leading from the other end of theradiator, means for producing a controlled suction effect in said exhaust pipe, means for utilizing said suction effect for introducing secondary air into the radiator at a point remote from the burner end there-' of and comprising a tube extending through a wall of the exhaust pipe and partway into the radiator, means comprising a casing around said exhaust pipe for supplying preheated air to the burner, and means operable to divert some of the preheated air to said tube.

WILLIAM M. HEPBURN. 

